[Ru(phen)2(dppz)] as an efficient optical probe for staining nuclear components

The ‘molecular light switch’ complexes Ru(bpy)₂(dppz)]²⁺ (1) and Ru(phen)₂(dppz)]²⁺ (2), where bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline and dppz = dipyrido3,2-a:2′,3′-c]phenazine, have been explored as probes for diagnosing and staining nuclear components. The phen complex acts as a better staining agent for nonviable cells than for viable cells and exhibits a staining efficiency in tail region of comet more specific and stronger than the already known dye Hoechst 33258.